Bovine babesiosis
Author: Prof Banie Penzhorn
Licensed under a Creative Commons Attribution license.
Introduction
Two species are economically important in southern
Babesiosis is one of the most important tick-borne
Africa: Babesia bovis (which causes Asiatic redwater
diseases causing economic losses in cattle-production
and is transmitted only by R. (B.) microplus) and
systems
and
Babesia bigemina (which causes African redwater and
subtropical regions, where it is caused by both Babesia
is transmitted by both R. (B.) microplus and R. (B.)
bigemina and Babesia bovis. In Northern Europe,
decoloratus). Babesia divergens (transmitted mainly by
bovine babesiosis is caused by Babesia divergens. In
Ixodes
cattle, the parasites only occur in erythrocytes, and
organism in Europe.
world-wide,
especially
in
tropical
ricinus)
is
an
important
disease-causing
haemolysis is the primary mechanism leading to the
development of clinical signs.
European, Sanga and Zebu breeds are all susceptible,
and all develop latent infections after recovery.
Salient features of bovine babesiosis
European breeds can retain B. bovis infections for life
Bovine babesiosis is a tick-borne disease of cattle
and remain infective for ticks for up to two years, while
caused by intra-erythrocytic protozoan parasites of the
most cattle with a significant Zebu content lose the
genus Babesia. The disease, which usually has an
infection within two years. Babesia bigemina infections
acute onset, is characterized by fever, anaemia,
rarely persist for more than a year, regardless of the
icterus, haemoglobinuria (hence the common name
host, and infected cattle remain infective for ticks for
redwater),
only four to seven weeks.
splenomegaly,
hepatomegaly
and
(occasionally) nervous signs. If the animal is not
treated promptly, it may die.
Where does bovine babesiosis occur?
Babesia bigemina and B. bovis occur in Central and
South America, parts of Europe and Asia, Australia and
Africa. After R. (B.) microplus and R. (B.) annulatus
were eradicated in the USA, bovine babesiosis no
longer occurs in that country. In southern Africa, B.
bovis is restricted to areas where R. (B.) microplus is
prevalent, usually the higher rainfall areas in the
eastern parts. Due to its wider vector range, B.
bigemina is much more widespread and is present
Opened urinary bladder of a bovine, showing
haemoglobinuria
throughout southern Africa, except for the more arid
and some high-lying parts. Babesia divergens occurs in
the British Isles and northern Europe.
What triggers an outbreak of bovine babesiosis?
However, if treatment is delayed, supportive therapy
A clinically inapparent form of the disease is common
may be essential if the animal is to survive.
in young animals, and recovered animals become
latent carriers for variable periods. Recovery is
followed by a lasting immunity. This situation often
occurs in areas with high tick densities, and results in
an endemically stable situation: virtually all cattle are
latent carriers, but few clinical cases occur. An
important factor in the establishment of endemic
stability is the age of first exposure: Calves have a
natural resistance during the first six to nine months of
Babesia bovis in a blood smear
life and rarely show clinical signs, yet develop solid,
long-lasting immunity. This is also the ideal age at
Find out more
which calves should be vaccinated.
The
full
CPD
epidemiology,
Outbreaks generally occur when susceptible animals
course
contains
pathogenesis,
pathology,
Other relevant CPD courses
population. This can occur through intensive tick-

Heartwater
control strategies, or due to natural causes, e.g.

Theileria parva infections
prolonged drought. This allows a cohort of calves to
grow up in the absence of infection, which renders
them fully susceptible. When tick populations increase
again, outbreaks of babesiosis results.
Prevention and control
Eradication of the tick vectors (the so-called minimum
disease situation) is the most desirable, permanent
solution to the problem but is rarely considered
practical or economical. The alternative approach is
allowing endemic stability to develop. In the long-term,
this approach can be achieved by integrating the
strategic use of acaricides, the application of vaccines
in endemically unstable conditions and the use of tickresistant breeds of cattle.
Diminazene and imidocarb are the two main drugs
used
for
treating
clinical
cases
and
for
chemoprophylaxis. Recovery is the rule if specific
treatment is given early in the course of the infection.
on
the
diagnosis,
treatment, control and prevention of bovine babesiosis.
are brought into an endemic area or where endemic
stability has been disturbed by reduction of the tick
details